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The driving force shown here as ' ' is expressed in units of moles per unit of volume, but in some cases the driving force is represented by other measures of concentration with different units. For example, the driving force may be partial pressures when dealing with mass transfer in a gas phase and thus use units of pressure.
Diagram showing the ionic concentration and potential difference as a function of distance from the charged surface of a particle suspended in a dispersion medium. Zeta potential is the electrical potential at the slipping plane. This plane is the interface which separates mobile fluid from fluid that remains attached to the surface.
Differences in the concentrations of ions on opposite sides of a cellular membrane lead to a voltage called the membrane potential. [5] Many ions have a concentration gradient across the membrane, including potassium (K +), which is at a high concentration inside and a low concentration outside the membrane.
Fick's first law relates the diffusive flux to the gradient of the concentration. It postulates that the flux goes from regions of high concentration to regions of low concentration, with a magnitude that is proportional to the concentration gradient (spatial derivative), or in simplistic terms the concept that a solute will move from a region of high concentration to a region of low ...
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
Potassium is the major cation (K +, a positive ion) inside animal cells, while sodium (Na +) is the major cation outside animal cells.The difference between the concentrations of these charged particles causes a difference in electric potential between the inside and outside of cells, known as the membrane potential.
The horizontal axis is the concentration of the ligand. As the Hill coefficient is increased, the saturation curve becomes steeper. In biochemistry and pharmacology, the Hill equation refers to two closely related equations that reflect the binding of ligands to macromolecules, as a function of the ligand concentration.
Note that this simple theory predicts that this contribution to the diffusiophoretic motion is always up a salt concentration gradient, it always moves particles towards higher salt concentration. By contrast, the sign of the electric-field contribution to diffusiophoresis depends on the sign of β ζ {\displaystyle \beta \zeta } .